The article “Diode pumping of a continuous-wave Pr3+-doped LiYF4 laser” by A. Richter et al., Optics Letters, vol. 29, No. 22, pages 2638 to 2640, Nov. 15, 2004 discloses a laser comprising Pr:YLF as linear conversion material for converting blue light into green laser light with a wavelength of 523 nm. Pr:YLF has a narrow absorption band being smaller than 1 nm, and for pumping this linear conversion material blue pump light has to be used, which has a wavelength within this narrow absorption band. Pumping light sources can generally not be produced with such a high wavelength accuracy. Thus, after an amount of pumping light sources have been produced, it has to be checked which of these pumping light sources provide blue pump light within the narrow absorption band of Pr:YLF and these pumping light sources are then chosen for assembling the laser. Only a relatively small amount of the produced pumping light sources can therefore be used for assembling the laser.